Dissociative identity disorders: What is it and how is it caused?

Posted byimperialbiosciencereviewPosted inEditors' Picks, Neuroscience

By Gio Chang

Dissociation is a mental process in which an individual may disconnect from their thoughts, memories, feelings, and the surroundings (Wiginton, 2019). This is something that everyone would have experienced before, but dissociative disorders, on the other hand, are a group of mental disorders in which people have severe dissociations such that there are problems in carrying out everyday functions (Mayo Clinic Staff, 2017; Wang, 2018). According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), there are three main types of dissociative disorders: dissociative amnesia, depersonalisation-derealisation disorder, and dissociative identity disorder (Black & Grant, 2014).  

Dissociative identity disorder (DID), formerly known as multiple personality disorder, is a condition characterised by having two or more distinct identity or personality states. (AAMFT, n.d.) These different states usually have different names, characteristics, and mannerisms, (AAMFT, n.d.; NAMI, 2020) and a person with DID may feel like there are one or more voices in their head trying to take control (NAMI, 2020). People with DID generally do maintain their original identity, which is more likely to have a passive role, with the shifts in their identity or personality states generally occurring in the presence of a certain stressor or trigger (www.medicalnewstoday.com, 2020). As people with DID shift through their different identities and personalities, they frequently experience memory loss for certain periods of time, have gone through events which they were not aware of, and episodes of feeling disconnected from their body (AAMFT, n.d.). Other symptoms include hallucinations, sudden return of memories of traumatic events, and the fluctuation in the levels of functioning from the ability to carry out everyday skills effectively to nearly disabled (AAMFT, n.d.). People with DID may also have problems with depression, mood swings, anxiety, and unexplained sleep disorders (AAMFT, n.d.).

More than 90% of the DID cases are known to be caused by trauma, examples of such trauma are natural disasters, military combat or violence (Amen Clinics, n.d.).  However, it is also known that most of DID is caused by those experienced during childhood, including repetitive episodes of severe emotional, physical, or sexual abuse or by negligence brought about by the absence of a safe and nurturing upbringing (AAMFT, n.d.). Because the human brain continues to develop until approximately age 25, it goes through many stages of growth in which we learn and absorb everything around us. This includes coping mechanisms where we are able to process and regulate emotions and thoughts, but trauma prevents this process occurring and progressing (Amen Clinics, n.d.). It seems as if children of pre-school (age 4-5) and pre-adolescence age (age 8-9) are especially more at risk of dissociating and developing DID in response to ongoing trauma. The development of alternative personalities and identities are thought to be a type of coping mechanism for these individuals which allow them to disconnect from the trauma (Amen Clinics, n.d.). In people with DID, this is carried out by splitting, which is the creation of a new identity, for example, a child who had gone through repetitive physical abuse from their parents may create a new identity and project their fear and trauma onto this new identity (DID Research, n.d.). This is the child’s way of surviving as their brain has not yet learned how to process and manage the situation and is therefore a way for them to cope with the trauma. The theory of structural dissociation, however, puts a slightly different explanation forward. It states that children are not born with a unified personality, but rather have different states for different emotions and needs, such as happiness, anger, and hunger. These states unify as the children develop, but recurrent trauma may inhibit this process, leaving the person with multiple states of identities (Mental Health Today, n.d).   

The neuroanatomy behind DID and trauma caused by childhood abuse and neglect have been found to have a lot of overlapping areas. The changes in brain structure caused by repetitive childhood abuse includes a decrease in size of the hippocampus, which is an area of the brain important for learning and memory, a smaller prefrontal cortex, an area that is responsible for regulating behaviour and emotions and perceptions, and an increase in activity as well as a decrease in the size of the amygdala, which is an area that manages emotions, especially those to do with fear, and determines behaviour in response to potentially stressful or dangerous situations. (Holmes, 2003; Blihar et al., 2020) Similarly, people with DID experience changes in a number of brain regions involved with attention, memory and emotions (Amen Clinics, n.d.). Through brain imaging studies, people with DID have been seen to have smaller brain volume in the hippocampus bilaterally (Amen Clinics, n.d.; Blihar et al., 2020). On top of this, a study revealed that participants who have recovered from DID has a much larger hippocampi than those who were not yet recovered (Blihar et al., 2020). The amygdala, again, is significantly smaller in people with DID (Blihar et al., 2020). The reduction in the size of the hippocampus and the amygdala is a part of the defence mechanism carried out to process the trauma and the situations that remind them of the traumatic event and to modulate the emotions (Krause-Utz & Elzinga, 2018; Blihar et al., 2020)

DID is a very rare psychiatric disorder. This may be the reason why it is misunderstood by so many people and surrounded by stigmas. By understanding that DID is normally developed as a coping mechanism in response to trauma, and that it is a disorder where people experience shifts in personality or identity states, we can break the stigmas surrounding this disorder. 

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